1. Field of the Invention
The present invention relates to a lock unit for a fluid coupling connecting and disconnecting apparatus in which, after completion of connecting a fluid coupling by means of a working force maintained in the same direction, a locking for holding such a connected state and its releasing are performed.
2. Description of Related Art
A fluid coupling connecting apparatus, is disclosed in U.S. Pat. No. 3,774,636. In that apparatus, an access of a traveling truck to a fixed frame permits a male coupling which is not only fixed to the traveling truck but also connected to a fluid piping and a female coupling which is connected to the fixed frame to be connected to each other, while a detachment of the travelling truck from the fixed frame permits such a connection to be released.
Since there is no unit for locking the traveling truck and the fixed frame to each other in the aforementioned fluid coupling connecting apparatus, there is a danger of separating them from each other during passing of fluid after a connection of the male coupling and the female coupling has been made.
In order to prevent that danger, a fluid coupling connecting apparatus equipped with a lock unit is disclosed, for example, in Japanese Patent Provisional Publication No. SHO-61 236991. The apparatus of Japanese Patent Provisional Publication No. SHO-63-236991 as shown in FIG. 11, comprises a fixed-side connector block 100 and a moving-side connector block 101, both of which confronting each other. The fixed-side connector block 100 includes a female connector 103 joined with a connection to a fluid pipings at one end 102 and an end receiver 104 mounted to the front end of the female connector 103. The moving-side connector block 101 includes a male connector 106 joined to another connection to a fluid pipings on the other end 105, a cylinder 107 for forward and backward movement fitted through the male connector 106, a block system 108 mounted to the forward and backward cylinder 107, a spherical seal body 109 mounted to face the end receiver 104, and a positioning means 110 for directing the seal body 109 to a position confronting the receiver 104. The joiner device is operated for use in which the positioning means 110 of the moving-side connector block 101 is first actuated to force the male connector 106 to face the fixed-side connector block 100 and then, a connecting cylinder 111 is actuated to move both the male connector 106 and the forward and backward cylinder 107 leftward of FIG. 11 so that the seal body 109 presses against the end receiver 104. Under this condition, compressed air is supplied through an inlet opening 107a in the forward and backward cylinder 107 to move an outer tube 107b of the cylinder 107 forward (see FIG. 12). As the outer tube 107b advances forward, the lock system 108 are pivoted to engage with a flange 104a of the end receiver 104 as shown.
According to the prior art described in the foregoing Publication, after the connecting cylinder 111 actuates the male connector 106 to press against the end receiver 104, the forward and backward cylinder 107 allows the lock system 108 to engage with the flange 104a of the end receiver 104. This procedure requires at least a couple of cylinders 111 and 107 installed, which will thus cause the system to be greater in size, intricate in operation, and high in cost. Additionally, it is understood that the two cylinders 111, 107 should be sequence controlled with accuracy to assure the connection of pipings. If not or when there is any inconsistency in the control, the movement for connection will go jerky.
Furthermore, the prior art is disclosed that the outer cylinder 107b of the forward and backward cylinder 107 is displaced leftward of FIG. 12 for engagement of the lock system 108 with the flange 104a of the end receiver 104, the compressed air supplied through the inlet opening 107a forces a piston 107c to move rightward of FIG. 12 and simultaneously, exerts a force of rightward pressing on the seal body 109 joined with the piston 107c. This will cause a decrease in the joining force between the seal body 109 and the end receiver 104 and accordingly, the sealing effect at the connection may be deteriorated.